Wheeled shovel loader

ABSTRACT

The present invention relates to a wheeled shovel loader that comprises a boom ( 3 ) capable of pivoting about an axis ( 4 ) as well as loading shovel ( 13 ) that can be actuated by a tilting structure ( 11, 12 ). According to this invention, at least one additional arm ( 7 ) connecting the boom ( 3 ) and the loading shovel ( 13 ) is hinged so as to be capable of displacement in the same way as a parallel linkage or parallelogram on said arm ( 3 ) under the action of at least a first connecting rod ( 8 ) and at least a second connecting rod ( 9 ). The shovel loader of the present invention comprises means for controlling the displacement of the additional arm ( 7 ) according to the angular position of the boom ( 3 ) relative to its pivot axis ( 4 ), as well as means for maintaining the loading shovel ( 13 ) in a horizontal position.

The invention concerns a wheeled shovel loader with the characteristicsof-the generic portion of claim 1.

These types of shovel loaders, which travel on, for example, wheels ortracks, are well known and are widely used. These shovel loaders areparticularly used for the loading of trucks with earth and buildingmaterials. During the loading of tall trucks or large dumping vehicles,particularly with lightweight bulk goods such as coal, coke, wood chips,garbage, etc., shovel loaders with a very large loading height areneeded. These types of shovel loaders have available, for example, ashovel pivot point of at least 5 meters over the road level. In order toattain this loading height, there are, on one hand, very large shovelloaders with correspondingly tall hinged long booms with a correspondingunloaded weight and a large engine output (for example, 30 tons unloadedweight at 300 horsepower) for the loading of heavy goods. However, theseshovel loaders are too large and too expensive for the loading of lightgoods. On the other hand, there are the so-called telescopic loaderswith light material shovels, which are not very well liked in practicebecause they are relatively slow and very susceptible to wear and tear.The telescopes used in telescopic stackers run in slides which wear outwhen exposed to dust and dirt and higher sliding speeds, leading tobreakdowns.

Proceeding from this, the invention has as its object the increasing ofthe loading height of a relatively small, mass-produced wheeled shovelloader in such a way that it is usable for the loading of tall truckswith light bulk goods without reduction of its stability.

To achieve this object, a shovel loader with the characteristics ofclaim 1 is suggested. According to this, the shovel loader has anadditional arm, connecting the boom and the tool, which is hinged on theboom so as to be capable of displacement in the same way as a parallellinkage or parallelogram by means of a first connecting rod and a secondconnecting rod. When the boom is pivoted upward, extension of the entireboom is achieved by operation of the additional arm hinged on the boom.According to the invention, the shovel loader furthermore has meansavailable for control of the position of the additional arm depending onthe angle of the boom relative to the boom swivel pin. These meansensure that the additional arm is only extended from its positionretracted onto the boom after a predetermined angle of the boom has beenreached, thereby preventing an extension of the boom which impairs thestability of the shovel loader. Through the further means providedaccording to the invention for keeping the loading shovel parallel,goods in the loading shovel are prevented from falling out when theloading shovel is lifted.

In an embodiment of the invention, displacement of the additional armfrom a position retracted onto the boom only occurs after the boom haspassed through its horizontal position as it pivots upward. This ensuresthat extension of the entire boom only occurs above the horizontalposition of the boom. Conversely, it is of course also ensured that, asthe boom moves downward, the additional arm is completely folded in, atlatest, before the boom passes through its horizontal position.

In an advantageous embodiment of the invention, the means for control ofthe displacement of the additional arm includes at least one anglesensor.

In another embodiment of the invention, the means for control of thedisplacement of the additional arm include at least one position sensor.

In a particularly advantageous embodiment of the invention, theadditional arm for extension of the loading shovel is displaceable in anessentially horizontal direction even below the horizontal position ofthe boom, with the boom able to be shifted into a so-called floatingposition to adjust for the circular path of the loading shovel caused bythe displacement of the additional arm. This measure allows theadditional arm to be displaced forward in, for example, specificsteering situations in which the shovel loader cannot be moved anynearer to the location of pickup and/or delivery of the goods to bemoved. Before the boom can be lifted from this position, the additionalarm must be completely retracted to maintain tipping resistance. Forthis purpose, an electric angle or position detector is advantageouslyprovided for release of the hub movement by the boom.

In a further embodiment of the invention, the lengths of the firstconnecting rod and the second connecting rod are essentially equal.

In another embodiment of the invention, the first connecting rod isshorter or longer than the second connecting rod. Due to the unequallengths of the first connecting rod and the second connecting rod, theend position of the additional arm in its completely folded out positioncan be influenced. If, for example, the first connecting rod, i.e., theconnecting rod hinged on the boom further from the chassis, is shorterthan the length of the second connecting rod, which is hinged on theboom closer to the chassis, the additional arm displays a relativelyflat positioning in relation to the completely raised boom.

Further advantageous embodiments are described in the sub-claims.

Of course, the characteristics mentioned in the preceding and describedin the following are not usable only in the combinations indicated, butalso in other combinations or alone, without leaving the framework ofthe present invention.

The invention is depicted with reference to an exemplary embodiment inthe drawings and will be described in more detail in the following withreference to the drawings.

FIG. 1 shows a shovel loader according to the invention in a side viewwith the boom completely retracted and completely extended.

FIG. 2 shows an enlarged view of the front section of the shovel loaderof FIG. 1 with the boom in an approximately horizontal position.

FIG. 3 shows an enlarged section from FIG. 1 of the front section of theshovel loader according to the invention with a completely retractedboom and a completely extended boom.

FIGS. 4a to 4 c show the horizontal displacement of the boom of theshovel loader according to the invention from FIG. 1 in a sequence inwhich the loading shovel is displaced forward along the floor.

FIG. 5 shows the shovel loader according to the invention from FIG. 1with a stacking fork as the tool replacing the loading shovel in ahorizontal displacement of the boom along a raised horizontal plane.

FIG. 1 shows a wheeled shovel loader 1 on tires according to theinvention with center pivot steering. Of course, the invention can alsobe realized with other conventional shovel loaders with axle pivotsteering, caterpillar tracks, and similar devices. A boom 3 is rotatablyhinged around a boom swivel pin 4 on a front section of the vehiclesuperstructure 2 (loading frame) forming the shovel loader 1 (cf. alsoFIG. 3). A first lifting cylinder 5 serving to pivot the boom 3 engageson one end on the loading frame and on the other hand approximately inthe middle of the boom 3. The components boom 3, boom swivel pin 4, andlifting cylinder 5 correspond as much as possible with the serial partsof a commercially available shovel loader.

According to the invention, the shovel loader 1 includes an additionalarm 7 whose length in the exemplary embodiment illustrated and describedis essentially somewhat shorter than the length of the boom 3. Theadditional arm 7 is hinged by means of a first connecting rod 8 and asecond connecting rod 9 on the boom like a parallel linkage orparallelogram in such a way that in its retracted position it liesdirectly on the boom 3 (cf. also FIG. 2). The connecting rods 8, 9 caneach be individual connecting rods or can also, in particular, besymmetrically positioned pairs of connecting rods. The first connectingrod 8 is hereby hinged on an end of the boom 3 further from the boomswivel pin 4 around a rotational axis 6, which is the shovel-tippingaxis of the serial boom 3, while the connecting rod 9 engagesapproximately in the region of the center of the boom 3. 1n theexemplary embodiment depicted, the hinge pin 18 of the second connectingrod 9 coincides on the boom 3 with the hinge pin of the first liftingcylinder 5, which can naturally be implemented differently in otherembodiments.

Each of the other ends of the connecting rods 8, 9 are positioned on theadditional arm 7, approximately in the region of the center of theadditional arm 7 (connecting rod 8) and on an end 19 pointing toward theshovel loader 1 (connecting rod 9). For displacement of the additionalarm 7 out of and into its retracted position on the boom 3, a secondlifting cylinder 15 is provided which is hinged on one end approximatelyin the center of the connecting rod 9 and on the other end on the boom 3and/or on the boom swivel pin 4. Of course, other linkages of the secondlifting cylinder 15, as well as the further actuator necessary foroperation of the entire boom and the loading shovel, are also possible.Both the first and the second lifting cylinder can be arrangements ofpairs of hydraulic cylinders, insofar as the size and/or the load to bemanaged by the loader require this.

On the end of the additional arm 7 opposite to the end 19, a loadingshovel 13 is pivotably hinged around a shovel hinge pin 10. Theoperation of the loading shovel 13 is performed by means of a tiltingstructure 11, 12 which includes a tilting lever 11 [sic] hinged on(approximately the center of) the additional arm 7 and a tilting bar 11connecting the tilting lever 12 with the loading shovel 13. Theoperation of the tilting structure 11, 12 is performed by means of atilting cylinder 14, which engages on one end on a central section ofthe tilting lever 12 and on the other end on the end 19 of theadditional arm 7 pointing toward the shovel loader 1. The loading shovel13, the tilting structure 11, 12, and the tilting cylinder 14 cancorrespond to normal serial devices and can differ from the exampledepicted.

Angle sensors 16 and 17, respectively, are positioned on the boom swivelpin 4 and on the shovel hinge pin 10. The angle sensors 16, 17 serve todetermine the relative angle between the boom 3 and the vehiclesuperstructure 2, and/or the attitude of the loading shovel 13 to theadditional arm 7. Electronic control of the hydraulic cylinders 14, 15is performed with reference to the angle and/or position valuesdetermined by the angle sensors 16, 17. The angle sensor 16 is acomponent of means for control of the displacement of the additional arm7, as is described in the following. Of course, other suitable sensorscould be used in place of the angle sensors described, for exampleposition sensors, which are preferably positioned on the boom 3 or onthe first lifting cylinder 5.

During operation of the shovel loader 1 according to the invention,after the loading shovel 13 is filled and tilted inward, the loadingshovel 13 is lifted by pivoting the boom 3 around the boom swivel pin 4by means of the first lifting cylinder 5. During this upwards pivotingmovement, the rotational axis 6 (shovel pivot point of the serialdevice) describes a circular path K1 (up to the highest position A) andthe shovel hinge pin 10 describes a circular path K2, which leadsthrough a horizontal position D. 1n the position D, the shovel hinge pin10 lies at the same height as the boom swivel pin 4 and the maximumextension appropriate for the minimum tipping load is achieved.

During the upward pivoting movement of the boom 3, the additional arm 7first remains inactivated in its retracted position on the boom 3, whilecontrolled operation of the loading shovel 13 is performed by means ofthe tipping cylinder 14 through an angle sensor 17 and control meansconnected with it, which are not depicted in more detail, in such a waythat the opening of the loading shovel 13 always points upward (parallelmaintenance function—cf. FIG. 2, in which the entire boom is illustratedin the position indicated in FIG. 3 with D).

After passing through the position D, i.e., after the maximum extensionhas been reached, a displacement of the additional arm 7 begins, after apredetermined angular position of the boom 3 has been reached, by meansof the second lifting cylinder 15, which is controlled via theelectronic control means connected with the angle sensor 16. 1n theexemplary embodiment depicted in the figure, the displacement of theadditional arm 7 occurs after a position B1 of the rotational axis 6 ofthe boom 3, which lies approximately 10° above the horizontal, has beenreached. Of course, displacement of the additional arm 7 can also beganin other positions, which, however, preferably all lie above the maximumextension, in order to prevent exceeding the maximum extension and/or toensure tipping safety, even during loading work on slightly slopingterrain.

The position B1 of the rotational axis 6 corresponds to a position B2 ofthe shovel hinge pin 10, which represents the end point of the circularpath K2 of the shovel hinge pin 10 up to this point, because now theshovel hinge pin 10 on the end of the additional arm 7 is moved upwardmore strongly than on the circular path K2 by operation of theadditional arm 7 and the extension associated with it. The parallelmaintenance function by hydraulic electronic equalization of the angularposition between the loading shovel and the additional arm 7 is therebyoverlaid with a folding out movement of the additional arm 7, so thatafter the position A has been reached through the rotational axis 6 ofthe boom 3, the shovel hinge pin 10 of the additional arm 7 has reachedthe highest position C.

As already mentioned in the preceding, conversely, during the downwardmovement of the boom 3, the retraction procedure of the additional arm 7is controlled in such a way that the additional arm 7 is againcompletely retracted by, at latest, when the position B1 has beenreached. This measure according to the invention ensures that themaximum extension reached in position D is never exceeded.

The horizontal displacement of the loading shovel below the horizontalposition of the boom 3 is depicted in the FIGS. 4a to 4 c. FIG. 4a showsthe shovel loader according to the invention from FIG. 1 in its initialposition with boom lowered and loading shovel 13 tipped outward. To takegoods L into the loading shovel 13, the shovel loader is typically movedin the direction of the goods L until a sufficient amount of goods is inthe loading shovel 13. 1f this is not possible due to, for example,unsuitable condition of the ground, then, according to the invention,the boom can now be moved forward by operation of the additional arm 7,as is depicted in FIGS. 4b and 4 c. For this purpose, the second liftingcylinder 15 is operated and the connecting rods 8, 9 are displaced.Simultaneously, the boom 3 is shifted into a so-called floatingposition, in which it is operated by means of the first lifting cylinder5 in such a way that equalization of the circular path of the loadingshovel 13 due to the displacement of the additional arm 7 occurs, sothat the loading shovel 13 moves along an essentially horizontal plane,determined by the ground.

When the loading shovel 13 has been moved far enough forward in this waythat it is sufficiently filled with the goods L (FIG. 4c), the filledloading shovel is tipped inward. Before the boom 3 can be lifted byoperation of the first lifting cylinder 5, the additional arm 7 must becompletely retracted again. This position corresponds to the positionillustrated in FIG. 4a, with the difference that the loading shovel 13is tipped upward. Only then can the lifting of the boom 3 proceed, asdescribed in the preceding in connection with FIGS. 1 to 3. An electricangle or path detector is preferably provided on the connecting rod 9 oron the second lifting cylinder 15 which registers the position of theadditional arm 7 and only releases the lifting movement for the boom 3when the additional arm 7 is completely retracted. Sufficient tippingsafety is thereby insured.

In FIG. 5, a corresponding use of the horizontal displacement along ahorizontal plane at a distance from the ground is illustrated usingstacking as an example. For this purpose, the loading shovel 13 in theshovel loader according to the invention of FIGS. 1 to 4 is replaced asthe tool by a stacking fork 13′. The horizontal movement of theadditional arm 7 according to the invention described in the precedingwith reference to FIGS. 4a to 4 c can also be utilized in this raisedposition, as is illustrated by the dash-dot illustration, without theshovel loader having to be moved forward or backward.

The particular advantage of the invention is based in that the shovelloader according to the invention can be obtained from a serial shovelloader with relatively simple means by replacement of the boom, withoutsignificantly changing the stability with an overlong boom and with allof the tools of the serial device still able to be used. A small serialshovel loader can thereby be used for high loading work according to theinvention, with the added weight of the additional arm compensated forby an additional counterweight (reference number 20 in FIG. 1).

The circular paths K1 and K2 can coincide in an advantageous case. If,however, they are separated from one another, as in the exemplaryembodiment depicted, this displacement of the centers of gravity mustalso be compensated for by the additional counterweight 20.

Of course, the invention is not restricted to the exemplary embodimentillustrated in the figures, but also includes other alterations inconstruction. In particular, the pair of connecting rods 8 and 9 do nothave to be essentially the same length, as in the embodiment depicted,but can also be implemented with different lengths. In addition, thenumber of connecting rods and their hinge points can be selected freelywithout leaving the framework of the invention. Furthermore, the boom 3and/or the additional arm 7 can be equipped as desired, for example as aso-called mono boom, with hollow body box design, or as a frame formedfrom two side parts, as shown in the example.

What is claimed is:
 1. A wheeled shovel loader comprising: a) a boom,said boom adapted to pivot; b) a loading shovel; c) a tipping structure,said tipping structure operatively associated with said loading shovel;d) at least one additional arm, said at least one additional armextending between and connecting each of said boom and said loadingshovel, e) at least one first connecting rod and at least one secondconnecting rod, said at least one first connecting rod and said at leastone second connecting rod cooperate to hingedly connect said at leastone additional arm to said boom and extending therebetween so that saidat least one additional arm is adapted to be selectively displacedrelative to said boom between a retracted and extended position in themanner of a parallel linkage or parallelogram upon movement of said atleast one first connecting rod and at least one second connecting rod;f) a lifting cylinder for retracting and extending said at least oneadditional arm, said lifting cylinder connected at one end thereof to atleast one of said boom and a vehicle superstructure of said shovelloader and connected at an opposite end thereof to at least one of saidat least one first connecting rod and said at least one secondconnecting rod; and g) a displacement control, said displacement controloperatively associated with said at least one additional arm forselectively controlling the position of the same in response to theangular position of said boom relative to said shovel loader wherebysaid loading shovel is maintained in a desired position relative to saidat least one additional arm.
 2. A shovel loader as in claim 1 andwherein said at least one additional arm may be displaced from theretracted position only after said boom has passed through a horizontalposition relative to said wheeled shovel loader.
 3. A shovel loader asin claim 1 and wherein said displacement control includes at least oneangle sensor.
 4. A shovel loader as in claim 1 and wherein saiddisplacement control includes at least one position sensor.
 5. A shovelloader as in claim 1 and wherein said at least one additional arm isadapted to be displaced within an essentially horizontal plane relativeto said shovel loader when said boom is caused to be shifted into afloating position so that movement of said loading shovel followingdisplacement of said at least one additional arm is caused to becompensated for.
 6. A shovel loader as in claim 5 and furthercomprising: a) an electric angle or position sensor, said electric angleor position sensor is operatively associated with said boom to permitlifting movement thereof when said at least one additional arm is in theretracted position.
 7. A shovel loader as in claim 1 and wherein said atleast one first connecting rod and said at least one second connectingrod are substantially equal in length.
 8. A shovel loader as in claim 1and wherein at least one of said boom and said at least one additionalarm have at least one of a hollow box configuration or a lifting frameconfiguration comprising two side walls and a transverse connection. 9.A shovel loader as in claim 1 and further comprising: a) a boom liftingcylinder, said boom lifting cylinder connected at one end thereof to avehicle superstructure of said wheeled shovel loader and at an oppositeend thereof to said boom to provide pivoting movement of the same.
 10. Ashovel loader as in claim 1 and wherein at least one of said at leastone first connecting rod and said at least one second connecting rod hasa bent portion.
 11. A shovel loader as in claim 1 and further includinga boom swivel pin, said boom swivel pin for pivotally connecting atleast one of said boom and said one end of said lifting cylinder to avehicle superstructure of said shovel loader.
 12. A wheeled shovelloader comprising: a) a boom, said boom adapted to pivot; b) a loadingshovel; c) a tipping structure, said tipping structure operativelyassociated with said loading shovel; d) at least one additional arm,said at least one additional arm extending between and connecting eachof said boom and said loading shovel, e) at least one first connectingrod and at least one second connecting rod, said at least one firstconnecting rod and said at least one second connecting rod cooperate tohingedly connect said at least one additional arm to said boom andextending therebetween so that said at least one additional arm isadapted to be selectively displaced relative to said boom andindependently thereof between a retracted and extended position in themanner of a parallel linkage or parallelogram upon movement of said atleast one first connecting rod and at least one second connecting rod;and f) a displacement control, said displacement control operativelyassociated with said at least one additional arm for selectivelycontrolling the position of the same in response to the angular positionof said boom relative to said shovel loader whereby said loading shovelis maintained in a desired position relative to said at least oneadditional arm.
 13. A shovel loader as in claim 12 and wherein said atleast one additional arm may be displaced from the retracted positiononly after said boom has passed through a horizontal position relativeto said wheeled shovel loader.
 14. A shovel loader as in claim 12 andwherein said displacement control includes at least one angle sensor.15. A shovel loader as in claim 12 and wherein said displacement controlincludes at least one position sensor.
 16. A shovel loader as in claim12 and wherein said at least one additional arm is adapted to bedisplaced within an essentially horizontal plane relative to said shovelloader when said boom is caused to be shifted into a floating positionso that movement of said loading shovel following displacement of saidat least one additional arm is caused to be compensated for.
 17. Ashovel loader as in claim 16 and further comprising: a) an electricangle or position sensor, said electric angle or position sensor isoperatively associated with said boom to permit lifting movement thereofwhen said at least one additional arm is in the retracted position. 18.A shovel loader as in claim 12 and wherein said at least one firstconnecting rod and said at least one second connecting rod aresubstantially equal in length.
 19. A shovel loader as in claim 12 andwherein at least one of said boom and said at least one additional armhave at least one of a hollow box configuration or a lifting frameconfiguration comprising two side walls and a transverse connection. 20.A shovel loader as in claim 12 and further comprising: a) a boom liftingcylinder, said boom lifting cylinder connected at one end thereof to avehicle superstructure of said wheeled shovel loader and at an oppositeend thereof to said boom to provide pivoting movement of the same.
 21. Ashovel loader as in claim 12 wherein at least one of said at least onefirst connecting rod and said at least one second connecting rod has abent portion.
 22. A shovel loader as in claim 12 and further including alifting cylinder for retracting and extending said at least oneadditional arm, said lifting cylinder connected at one end thereof to atleast one of said boom and a vehicle superstructure of said shovelloader and connected at an opposite end thereof to at least one of saidat least one first connecting rod and said at least one secondconnecting rod.
 23. A shovel loader as in claim 22 and further includinga boom swivel pin, said boom swivel pin for pivotally connecting atleast one of said boom and said one end of said lifting cylinder to avehicle superstructure of said shovel loader.